The present invention relates to conveying and dispensing systems for non-liquid fluent material such as free-flowing packaging materials and, in particular, to a pneumatic conveyor system for recycling spilled material.
It is inherent to the dispensing operation of most high throughput air conveyor systems for fluent packaging materials that material is easily spilled. The material spilled while filling containers must then be swept or otherwise picked up and manually returned to the conveyor system, or discarded. Typically, to avoid spillage, each container is loaded in increments by repetitively opening a dispensing valve. Quite obviously, this approach is time consuming and labor intensive.
Several approaches are available for conveying and dispensing loose-fill, free-flowing packaging material. For example, Ply U.S. Pat. No. 4,116,491 discloses a hopper for feeding granular materials into a double-walled air conveyor which comprises a porous inner pipe and a concentric outer pipe which is mounted to the inner pipe on spaced, vented baffles. Pressurized air is applied to the center pipe to create a cushion between the pipes and to propel fluent material such as grain along the inner pipe.
Persson U.S. Pat. No. 4,242,015 discloses an air conveyor in which the top sheet of a plenum chamber has slits to direct the air flow and entrained granular material from a storage hopper onto a belt conveyor. Regarding dispensing, Cordes U.S. Pat. No. 3,188,146 discloses a hopper which dispenses granular washing products to an automatic washing machine. The materials are fed downward by gravity, then blown upward via an air lift tube into the wash tank Also, Stockel et al U.S. Pat. No. 3,261,379 discloses a pneumatic granular-type material dispensing system having a vent tube which incidentally acts to feed material back into a storage bin. While these patents may be of interest in defining the general state of the air conveyor art and the dispensing art, they do not provide a viable approach for automatically recycling free-flowing packaging material without spillage.